The Macroeconomic Imbalance Procedure (MIP) is part of a institutional framework known as the so-called "sixpack", which has come into effect on December 13th 2011 in response to the European financial and debt crisis. The crisis has shown that internal and external imbalances (in particular current account deficits) are strongly intertwined. The MIP should identify external imbalances at an early stage and thus compel countries to correct these imbalances to forestall potential crises. Methodological questions are discussed, which are to be resolved to ensure the effectiveness of the MIP.